Sex, race, age impact risk for treatment-resistant depression

Treatment-resistant depression prevalence varied by sex, race and age, according to results of a cross-sectional study published in Journal of Clinical Psychiatry.

“To evaluate the public health significance and disease burden of [treatment-resistant depression (TRD)] and develop effective pharmacologic treatments for TRD, it is essential to have an accurate and reliable estimate of TRD population size and risk factors,” Xinyue Liu, PhD, of Merck & Co. Inc.’s Center for Observational and Real-World Evidence, and colleagues wrote. “TRD epidemiology studies help researchers in designing clinical trials, so that patients enrolled in TRD trials will be more closely representative of the real-world TRD population. From the clinical practice perspective, the risk factors identified in TRD epidemiology studies can help psychiatrists assess the risk of TRD in patients with depression and better develop individualized disease management plans.”

The researchers sought to outline TRD prevalence using two large U.S. claims databases, Humana (n = 296,055 patients) and Optum (n = 277,941). They analyzed data of patients aged 18 years or older who had pharmaceutically treated depression (PTD), with at least one major depressive disorder diagnosis based on ICD-10-CM criteria and one antidepressant prescription filled in 2018. Liu and colleagues defined TRD as having treatment failure with two or more antidepressants with 4 weeks or longer of adequate treatment. They estimated the age- and gender-standardized prevalence of TRD and conducted logistic regression to determine whether TRD risk differed based on age, sex, race and geographic region. Further, they outline the timeline of TRD development among patients with incident PTD.

A total of 17,640 (6%) and 16,131 (5.8%) patients with PTD in the two databases had TRD. Following standardization for age and sex, Liu and colleagues found TRD prevalence of 6.8% in the Humana database and 5.8% in the Optum database among patients with PTD. Women, middle-aged adults and white patients had increased risk for TRD. The researchers noted media time from index antidepressant use to TRD of approximately 6 months among patients with incident PTD.

“The TRD patients were predominantly female and were between ages 45 to 64 years,” Liu and colleagues wrote. “Given the vast variation of TRD prevalence in publications, further efforts should be taken to standardize TRD definition.”